Wind Power Feb14

Wind Power

Wind Power Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and rotation of the earth. Wind flow patterns are modified by the earth’s terrain, bodies of water, and vegetative cover. Wind energy is the kinetic energy of air in motion. This wind energy can be harvested. Wind power is the conversion of this wind energy into a useful form of energy, such as electrical power by using wind turbines, mechanical power by using wind mills, pumping or drainage of water by wind pumps and as sails to propel ships. Wind energy is a renewable or non-conventional source of energy. This is clean and non polluting energy source. It is available in large amounts in many parts of the world. It does not generate any greenhouse gasses during the production of electricity. The total amount of economically extractable power available from the wind is very high.  Axel Kleidon of the Max Planck Institute in Germany carried out a ‘top down’ calculation on how much wind energy there is, starting with the incoming solar radiation that drives the winds by creating temperature differences in the atmosphere. He concluded that somewhere between 18 TW and 68 TW (Terawatt which is one trillion watts) could be extracted. Cristina Archer and Mark Z. Jacobson presented a ‘bottom-up’ estimate based on actual measurements of wind speeds. As per this estimate there is 1700 TW of wind power available at an altitude of 100 meters over land and sea. Out of this available power, between 72 and 170 TW could be extracted in a practical and cost competitive manner. They later estimated it to be 80 TW. However research at Harvard university estimates 1 Watt/Sq m on an average and...

Solar Photovoltaic Power Feb07

Solar Photovoltaic Power...

Solar Photovoltaic Power Solar photovoltaic (PV) power is a method of generating electrical power by converting solar energy radiation into direct current electrical power using semiconductors that exhibit the photovoltaic effect. Solar PV power is a renewable as well as sustainable energy source. Solar PV power is now the third most important renewable energy source after hydro and wind power in terms of globally installed capacity. Solar cells, also called photovoltaic cells by scientists, convert sun energy directly into electricity. PV gets its name from the process of converting light (photons) to electricity (voltage), which is called the ‘photovoltaic (PV) effect’. The PV effect refers to photons of light exciting electrons into a higher state of energy, allowing them to act as charge carriers for an electric current. The PV effect was first observed by Alexandre-Edmond Bequerel in 1839. The term photovoltaic denotes the unbiased operating mode of a photodiode in which current through the device is entirely due to the transduced light energy. Virtually all photovoltaic devices are some type of photodiode. The PV effect of silicon (an element found in sand) was discovered in 1954, when scientists at Bell Telephone discovered that silicon created an electric charge when exposed to sunlight. Solar energy is the most abundant energy resource on the earth. Direct conversion of sun energy into electric power in PV cells is one of the three solar active technologies. The other two technologies are ‘concentrating solar power (CSP)’ and ‘solar thermal collectors for heating and cooling (HSC)’. Today PV provides more than 0.1 % of total global energy generation. It has also promising future. Global PV capacity is increasing at an average annual growth rate of more than 40 % since 2000 and it has got significant potential for long term growth in coming years. Solar PV power is a commercially available reliable technology for...